As an apparatus related to the control of the boost converter in the power supply system for the vehicle, there is an electric motor drive control system disclosed in a Patent Literature 1.
According to the system disclosed in the Patent Literature 1, required minimum voltage VHmin of the boost converter is calculated on the basis of torque command values of a plurality of motor generators, which are loading apparatuses. A plurality of candidate values of output voltage of the boost converter are determined in a voltage range from the required minimum voltage VHmin to maximum output voltage VHmax of the boost converter. Moreover, in the system disclosed in the Patent Literature 1, a loss of an entire boost system including a battery, the boost converter, and the motor generators is estimated for each of the plurality of candidate values. A target value of the output voltage VH of the boost converter is set to a candidate value that minimizes the estimated loss. The Patent Literature 1 suggests that the system can minimize the power loss of the entire boost system.
Patent Literature 2 discloses an apparatus configured to prevent overshoot of a direct current (DC) voltage value on a motor drive apparatus using pulse amplitude modulation (PAM) control. This apparatus is capable of preventing the overshoot of the DC voltage value by reducing an increase value of a DC voltage command value if a DC voltage detection value approaches a predetermined value in a certain range.
Moreover, Patent Literature 3 discloses a voltage varying apparatus configured to vary a change ratio of the voltage command value on the basis of magnitude of the voltage command value. This apparatus is capable of preventing the overshoot of the output voltage by making the change ratio of the voltage command value smaller than a previous value if the voltage command value exceeds a threshold value.
Moreover, Patent Literature 4 discloses a control apparatus for a load drive system in which the output voltage of the boost converter can be kept even if operation of the boost converter is stopped in an extremely low load state.
According to this apparatus, switching operation of a converter is stopped when total load power, which is the sum of load powers of a plurality of loads, is a value in a predetermined range including zero. Moreover, when the total load power is the value in the predetermined range, a command that is outputted to any of load drive control units is corrected such that an absolute value of a deviation between a command value and the output voltage of the boost converter is reduced. Thus, the output voltage of the boost converter can be kept even if the operation of the converter is stopped in the extremely low load state. In addition, the loss of the boost converter can be reduced because the boost converter can be stopped in the extremely low load state or a no-load state.